Mario Livio Space Telescope Science Institute 1 Object Physical - - PowerPoint PPT Presentation

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Mario Livio

Space Telescope Science Institute

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Object Physical System Young Stellar Objects Accreting Star HMXBs Accreting NS or BH X-ray Transients Accreting BH LMXBs Accreting NS Supersoft X-ray Sources Accreting WD Symbiotic stars Accreting WD Pulsars Rotating NS Planetary Nebulae (?) Accreting Nucleus or Interacting Winds Ste tellar Object Physical System AGN Accreting Supermassive BH GRBs Accreting BH Ex Extr tragalacti tic

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Do FR I radio galaxies have relativistic jets like BL Lacs?

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• GRS 1915+105


V ~ 0.9c

• Some extragalactic

jets show
 V > 0.995c

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STScI-PRC99-32 Southern Crab Nebula
 He2-104

10 NGC 7009 NGC 6543 NGC 3918 NGC 6826 NGC 5307

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SS 433

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Chandra Crab Pulsar Vela Pulsar Chandra

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What are the absolutely necessary ingredients for the mechanism of jet acceleration and collimation?

YSOs Yes SSS Yes H/LMXBs Yes BHXTs Yes GRBs We don’t know AGN Yes PNe Not clear

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Redshifted component not seen because of disk.

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• MCG-6-30-15
• Gravitational redshift plus Doppler shift

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“Interacting winds”, “ion torus”, Pulsars, GRBs, need more work

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• Are outflows/jets the main mechanism for

transport/removal of angular momentum?

• Angular momentum carried by wind


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Angular momentum that needs to be removed from disk For rA ~ 10r, only 1% of the accreted mass needs to be lost in wind.

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• At outburst, matter diffuses inward.

Angular momentum of that matter is transferred to outer parts of the disk.

Radius expands
 Observationally:

• Disks in U Gem, OY Car,

HT Cas and Z Cha larger in outburst. U Gem

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Theory: disk instability

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Probably not. t.

• More observations of rotation in jets

and bipolar outflows are needed (velocity gradients).

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Jet Origin

Object Example Vjet/Vescape

YSOs HH30, 34 Vj ~ 100-350km/s Vesc ~ 500km/s ~1 AGN M87; radio sources


γ >~ 3; γ <~ 10

~1 GRBs

γ ~ 100

~1 XRBs SS 433; Cyg X-3 Vj ~ 0.6c ~1 XRTs GRO 1655-40
 GRS 1915+105
 Vj >~ 0.9c ~1 Pne Fliers, Ansae
 V ~ 200km/s ~1 SSS 0513-69
 Vj ~ 3800km/s ~1

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• Jets originate from the center of the

accretion disk!

• Models which work at all radii are

probably not the “correct” ones, (e.g. self similar).

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Two states: (i) dissipation and disk luminosity, (ii) bulk flow and jet.

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Timescale 
 for jet


tj ~ td2R/H

1/f power spectrum below a break frequency.

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Which ingredients play a major role in the acceleration and collimation?

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YSOs AGN XRBs SSS GRBs CVs Central object near break-up rotation No ? No, ? ? ? ? Relativistic 
 central object No Yes Yes No Yes No “Funnel” No (?) No (?) No (?) No Yes (?) No L >~ LEdd 
 (Radiation pressure)
 (wind can be driven) No No No Yes ? No Extensive hot atmosphere
 (gas pressure) Yes (?) Yes No No Yes (?) No Boundary layer Yes (?) No ? Yes (?) No Yes (?)

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A reasonably ordered large-scale magnetic field threading the disk!

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• 1. Acceleration like a bead on a

wire 
 up to the Alfven surface.

• 2. Acceleration optimal around

inclination of 60°.

B2 8π > ρν 2 ρν 2 > B2 8π

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Collimation by hoop stress?

BUT

Kink Instability

2 2

( )/8

z

B B

φ

π −

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Necessary Conditions

• 1. Rdisk/Robject = Significant number of decades
• 2. Bz largest at inner disk but 


largest at outer disk e.g. Bz ~ (r/Rin)-1 Good collimation obtained for
 RAlfven ~ Rdisk Consequences Minimum opening angle of jet
 Θmin ~ (Rin/Rout)1/2

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• 1. Why are there radio-loud and

radio-quiet AGN?

• 2. Why do CVs appear not to produce

jets while SSS do?

• 3. How can pulsars produce jets?

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• The production of powerful jets

requires an additional heat/wind source.

• Solutions to transsonic flow in disk

corona: for strong B a potential difference exists even for i > 30 (Δφ ~ B4).

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Central engine
 parameters:

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• Outgoing velocity ~0.4 - 0.6

c in funnel wall jet

• Poynting flux dominates

within funnel

• Both pressure and Lorentz

forces important for acceleration

• Existence of funnel jet

depends on establishing radial funnel field

• Jet luminosity increases with

hole spin – Poynting flux jet is powered by the black hole

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a/M ηEM

• 0.9

0.023 0.0 0.0003 0.5 0.0063 0.9 0.046 0.93 0.038 0.95 0.072 0.99 0.21

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• RISCO, a*, determined on the basis of x-ray

continuum data (even beyond thermal- dominant state).

• Study of plunging orbits important. Spin

estimates based on stress-free inner boundary condition give upper limit on a*?

Source

M (Mʘ) a*

1655-40 6.3+-0.27 ~0.7 1543-47 9.4+-1.0 ~0.8 LMC X-3 ~7 <0.26 M33 X-7 15.65+-1.45 ~0.77 1915+105 14+-4.4 >0.98

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• 1. Determinations of the collimation scale in all

classes of objects.

• 2. Detection and measurement of rotation and of

toroidal magnetic fields in jets and bipolar

• utflows.
• 3. Searches for jets in other SSS, in PNe, in other

XRTs (during flares, e.g. A0620-00, GS2023+338, GS 1124-683, Cen X-4, AQL X-1), and other symbiotic systems, in CVs!

• 4. Determination of black hole masses in AGN.
• 5. Determination of black hole spins.
• 6. Observations of collimated jets in pulsars.
• 7. Afterglow light curves and breaks in GRBs.
• 8. Differences between short and long burst in GRBs.